System of grouping units



April 10, 1928. 1,665,499

E. T. HOCH SYSTEM OF GROUPING UNITS Filed March 1926 iii - In venfo r:

Ellery T l'10c/7 by W /7/I j.

Patented Apr. 10, 1928.

UNITED STATES PATENT OFFICE.

ELLERY T. HOCH, OF BLOOMFIELD, NEW JERSEY, ASSIGNOR 'lO BELL TELEPHONE i LABORATORIES, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

SYSTEM OF GROUPING UNITS.

Th-is'invention jrelatesitofa system of connecting units such .for-eicam'ple as condenser units to cover a iven range of values.

The object o 'this inventionis to provide' a system lof -'gi"oup'i 'ig 'or connecting units, having wide manufacturing limits, which will cover a given -range of values with small intervals betweenlsuccessive steps.

There" are," atl. present, two main systems of grgnipingi'1i' it;s:,';one of which, known as thefdecadefsystem, has [units of 1X, 2X, 3X, 4X, 10X, '2OX,1 etc. qv'hile the other system follows ageometric progression having units whose values*' are'1X,.2X, 4X, 8X, 16X, etc. The latter system has the advair tage of'covei'ingga' greater range with the same 'nuiiiberi of ;f the; decade system covering a raiiige' o'f IOQjwith. four units or 110K with eight units, while the geometric progression system poversta range of with four-units anii,255Xfwith eight units;

In either of tl ies"ef system s, however, the units must be ac'ciir atetof within plus or minus 5 offthefir nominal valueto avoid lar'ge intervals between steps, in.case the valu'eiofo'ne' unmask-low and the value of the next succeeding "ii nit is' high." With the necessity of such close' limits these systems are not desirable-where quantity production of the units is required.

'VVhile theabo've systems use but one unit. in each step, this invention contemplates the use of two or more units in a group corresponding to a step of the above system, and while maintaining small intervals between successive stepsjcomparable with the inter vals of the above system',"pei'mits the use of units varying as much "as plus or minus 33%% of the nominal value. Therefore quantity production of these units is possible, since such wide limits do not require great manufacturing accuracy. With-a permis sible variation of 33 the upper limit of each group will be twice its lower limit; that is, if the nominal value of a group is l X, the lower or minimum limit of the group will be X and the upper or maximum limit will be 2X. In the next succeeding group, the minimum limit will be the maximum limit of the preceding group or 2X and its maximum limit will be 4X for a nominal value of 3X. In

other words,- in a group having a nominal value of 1 /;X, each unit in the group may have any value between X and Ak -and -'for a nominal value of 3X, the units may have any value between 2X and 4X.

With such a grouping the greatest interval tion is attained; i. e. that-each= unit in a group has the nominal value of-the'= group, such a system would be a First mup 1 'X i QX Second group X Third group 6 X 6 IX Fourth group l2 X 12 It will readily be seen that values may be obtained from 1 X 'tothe greatest value of the system in intervals of 1%X.-

As stated above, the greatest intervals between succeeding steps should not exceed the upper limit of the smallest'value group. The upper limit in any group is 33%,% higher than its nominal value, so that for the smallest group in the above case the 'upper limit is 2X. Therefore, systems in which both units of each group have the nominal value will satisfy the condition.

In a secondexample let it be assumed that one unit of each group has the minimum value and the other has the maximum value. The following represents such a system:

First group X 2X Second group 2X 4X Third group 4X 8X Fourth group 8X 16X In such a system values from X to the maximum of the system may be Obtained in intervals of X. As the allowed intervals is the upper limit of the smallest group, or 2X, this system also satisfies the condition.

The worst condition which may be met is a system in which both units of one group have the minimum allowed value, while the.

units of the next succeeding group have the maximum allowed value. Such a system is represented as follows:

X X-both minimum'valuc) 4X 4X both maximum value) Third group 6X 6X--(b0th nominal value) Fourth group M 16X 16X(b0th maximum value) The. particular application ofthis system.

is .jin'. ,conne ction ,with condenser units, jalthough .it is ;not limited. to such, but may apply. toresistanceamils, inductance units, etc; in the electrical fart, and may find numerous applications in otherarts.

(lbndensers fgrouped in accordance with thisiriventiom are. particularly. adapted to carrier telephone systems where it is desired to havempluralityof capacity units, which may be combined to give any desired value within a certain -range,- while maintaining the necessary accuracy.

The manner of connecting he units willbe better understood by referring to the attached drawing, in which, Fig. lrepresents schematicailyf condenser units arranwed in accordance with'this invention'and' i ig. 2

. represents; schematically the topofafcon denser group which has'becn potted'showing the location of the terminals:

Each unit has one of its terminals brought out for external connection. Condenser unit X has one side connected to terminal 1, unit 2X to terminal 2, unit 2X.v to tcrmina. 3X, etc. The other side of each unit isconnected to a common terminal marked G. Fig. 2.shows the terminals arranged in a commercial unit. After it has been decided what the capacity is to be, the terminals of the uni-ts which will give this capacity are. strapped. For instance, if the capacity desired is 9X, terminals land 6 are strapped: for 10X either terminals 2 and 6,' or 3 and G are strapped. From this, it is readily seen how any value within the range of the group may be obtained by strapping the proper terminals.

\Vhat is claimed is:

1. Electrical apparatus comprising groups of a plurality of electrical units, each, the maximum permissible value of the individual units of each group being twice the minimum permissible value, the .miniinum permissible value oi the units of each succccding group being the maximum permissible value of the preceding group.

2. Electrical apparatus com prising groups of two units each, the maximum permissible value of"the iiicividual electrical units of each group being twieethe minimum permissible value, the minimum permissible value of thcu'nits of each succeeding group being-the maximun'i permissible value of the preceding roupi 3. Electrical apparatus comprising grou s of two units each, the maximum limit of the individual electrical units ofeach group bein'gtiviee the niinii'num limit, the minimum limit of the individual units of each sueceediiig g'i oupbeing the maximum limit of the units of the preceding group, the maximum intervalbetivee'n any one step and the next succeeding step not exceeding the maximum limit ojf' tiie values of the units of the group having tl e'sma llest valuel Electrical apparatus comprising groups of two electrical units each, each uiiit having a nominal value from whuh it may'vary an;

amount not t'o exceed plus or minus 33 576, the minimum limit of the value of the units of any group being the maximum limit of the value of the units of the preceding group, said groups giving progressive steps, the maximum,interval'betiveen successive steps 'not exceeding the maximum limit of the values of. 'thi-imits of thesmallest valued group. i

5. Electrical apparatus comprising groups of two electrical units each, each unit having a nominal value from which it may vary an amount not to exceed plus or minus 315M 7 the nominal value of each successive group, being twice the nominal value of the preceding group, said groups giving progressive steps, the maximum interval between successive steps not exceeding the maximum limit of the values of the units of the smallest valued-group. s

In witness whereof, I hereunto subscribe my name this 10th day of March A. D., 1926.

ELLERY '1". noon.

IOU 

